average hp gain

Jordo!

Across dynos and vehicles, here is what I have found to be the approximate range of % gains over baseline:

Typical intake +2.5 to +3.5% gain (best bang for the buck = K&N panel + smooth intake tubes)

Typical CBE = +1.5 to +3.5% gain (best bang for the buck, used Nismo CBE)

Typical TP/HFC = +4% to +5% gain (slightly more if LTH header instead) (Best bang for the buck - ebay TP's)

Tune = +3% to +5% gain (best bang for the buck - Osirus uprev)

Exact % gain will vary somewhat from vehicle to vehicle and throughout the rev range.

Gains are approximately cumulative; the first breather mod will usually show greater % gains than when the same mod is added later (i.e., 2nd or 3rd bolt on), probably due to diminishing returns as optimal VE is achieved.

Note: Don't get hung up on these seemingly small % increases; remember, on a 275 whp motor, a gain of 5% = nearly 14 whp; a cumulative gain of 10% is over 27 whp (more if you keep adding onto the last value obtained).

On a dynojet, you will see fully bolt-on'd tuned Z's putting down over 300 whp with SAE correction; the highest typically have LTH and lightweight pulleys (not sure if I would recommend those or not, tho'...).

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